According to the bank the guarantees, comprising $500m from the International Development Association (IDA) and $200m from the International Bank for Reconstruction and Development (IBRD), represent a “unique combination”.

The IDA guarantee “supports timely payments” for eventual gas purchases from the fields by the Ghana National Petroleum Corporation (GNPC) while the IBRD guarantee “enables the project to secure financing from its private sponsors”, the bank said.

The vice-president for the bank’s Africa region Makhtar Diop said: “The Sankofa gas project is a good example of how Africa can address its infrastructure challenges and lay the foundation for sustained economic growth by providing affordable and reliable power to its population. Innovative use of the bank’s guarantee programme that helps mitigate the perception of risk and mobilises private investment can help unlock billions of much-needed financing for large-scale infrastructure projects on the continent.”

Ghana’s finance minister Seth Terkper said Sankofa will be “a game changer” for Ghana and other middle income sub-Saharan African countries as it is set to shape the country’s energy sector for the next 20 years.

Terkper said: “This project is an essential element of the drive towards consolidating our middle income status, and will help secure our natural gas resources for a more affordable and reliable power supply. This will help boost economic activity and generate more jobs for Ghanaians. It is part of the smart financing we have been talking about, and we are very grateful to the World Bank Group for this major achievement.”

Vitol said the development is part of five fields comprising the ‘Offshore Cape Three Points’ (OCTP) integrated oil and gas project.

The fields “contain enough gas to continuously supply Ghana’s thermal power sector until at least 2036”, Vitol said. “The non-associated gas will be produced at high rates, supplying both new and existing power plants, substituting crude oil and fuel oil and providing an environmentally cleaner and more efficient fuel for the country”. OCTP “will access approximately 1.5 trillion cubic feet of gas-in-place and around 500 million barrels of oil-in-place”.

Engineering design for the project has been completed and the project has started, Vitol said. First oil and gas production “will be phased through 2017 and early 2018 and oil production will reach around 80,000 barrels of oil equivalent per day in 2019".

“Once the Sankofa field starts to produce gas in early 2018, Ghana will be able to reduce its oil imports by up to 12 million barrels a year and cut carbon emissions by 1.6 million tonnes of CO2 annually,” Vitol said.

A report released earlier this year by the Ghana Institute of Governance and Security, ‘Four Years of Oil Production in Ghana’, said the country received more than $2.7bn in total revenue from the oil sector after four years of production activities under the country’s ‘modern concession system’. However, the report said the figure could have been around $6.4bn if the country had adopted production sharing agreements.